Rotary electric machines have been used for vehicles. One type of the rotary electric machines is disclosed in U.S. Patent Publication No. 6,784,583 corresponding to Japanese Unexamined Patent Publication No. 2002-247787. The rotary electric machine disclosed in the U.S. Patent Publication has a stator coil consisting of a pair of first and second sets of three-phase windings. The three-phase windings of the first set have junctions serially connected to each other in delta (Δ) configuration, and the three-phase windings of the second set have output and input ends; these input ends are respectively connected in series to the junctions of the delta-connected three-phase windings of the first set.
Use of the above structured first and second sets of three-phase windings allows the number of turns of each winding to be freely set. For example, the number of turns of each winding of the first and second sets is different from that of turns of each winding of normally star-connected three-phase windings.
The U.S. Patent Publication No. 6,784,583 also discloses a stator coil having a configuration with first and second groups of first and second sets of three-phase windings. In this U.S. Patent Publication, a modification of the configuration in which the first group of the first and second sets of three-phase windings is shifted from the second group of those of three-phase windings by an electric angle of π/6 radian in phase is disclosed. This modification permits magnetic noise caused from the first and second groups of three-phase windings to decrease.
Another one type of the conventional rotary electric machines is disclosed in U.S. Patent Publications No. 6,800,974 and No. 6,617,723, which correspond to Japanese Unexamined Patent Publication No. 2003-180048. The rotary electric machine disclosed in these U.S. Patent Publications consists of first and second sets of normally star-connected three phase windings.
In the U.S. Patent Publication No. 6,784,583, wiring configuration of the three-phase windings of the first and second sets of the pair of the stator coil is schematically illustrated in FIG. 6 of the Patent Publication as an example. Specifically, in FIG. 6 of the Patent Publication, arrangement of connections between the junctions of the three-phase windings of the first set of the pair and the input ends of the three-phase windings of the second set thereof by leads is illustrated.
The U.S. Patent Publication No. 6,784,583, however, provides no specific examples of wiring configuration for the three-phase windings of the first and second sets of each of the first and second groups of the stator coil.
Accordingly, there is a need for providing such a specific example of wiring configuration for the three-phase windings of the first and second sets of each of the first and second groups of the stator coil in order to increase the usefulness of the stator coil set forth above.
Particularly, because the number of three-phase windings of the first and second sets of each of the first and second groups of the stator coil is larger than that of three-phase windings of the first and second sets of the pair of the stator coil, a more simplified wiring configuration is needed.